Magnetoconductance of planar cuprate superconductor/graphene junctions

Graphene/superconductor junctions have been extensively studied using low-T_c superconductors, but studies involving high-T_c temperature cuprates are scarce despite their interest for instance the rich physics expected from the d-wave order parameter. Here we study planar high-T_c superconductor/graphene junctions fabricated by transferring CVD graphene onto optimally doped c-axis PDL grown YBaCuO_7-x films, which are patterned using electron lithography and ion irradiation. Transport measurements at low temperature revealed an interesting, anomalous behavior of the magnetoconductance, which first increases at low magnetic fields before remaining constant or decreasing depending on the samples. This effect highly depends on temperature and voltage bias applied to the junction. We will discuss the different scenarios allowing for an understanding of this behavior.